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Temperate seagrass carbon-stock data remain limited in northern China, especially for island meadow systems with mapped distribution and repeated field verification. This study quantified standing seagrass ecosystem carbon stocks in the Changshan Archipelago, Dalian, using a standardized field survey covering eight meadow zones, 39 sampling stations, and 323.37 ha of confirmed seagrass area. Plant biomass carbon and sediment organic carbon were assessed, and the 0–100 cm sediment profile was sampled at all stations. The mapped meadows stored 29,305.75 Mg C in total ecosystem carbon. Sediment organic carbon accounted for 28,965.71 Mg C, representing 98.84% of the total stock. Plant biomass carbon contributed 340.04 Mg C, or 1.16%. The area-weighted ecosystem carbon stock per unit area was 90.63 Mg C ha[sup.−1]. This per-area stock ranged from 52.11 Mg C ha[sup.−1] in Xiaochangshan to 209.50 Mg C ha[sup.−1] in Haiyang Island. Guanglu Island contained the largest total carbon stock, with 9247.73 Mg C, because of its large meadow area and relatively high per-area carbon stock. The results show how mapped meadow area, sediment carbon dominance, and local sediment setting jointly shape regional carbon-storage patterns. This standardized baseline provides field-based evidence for comparing northern Chinese seagrass meadows with other temperate Zostera systems. The estimates describe standing ecosystem carbon stocks. Annual carbon sequestration rates were outside the scope of the assessment.

The marine ecological red lines (MERLs) is an institutional innovation of the Chinese government to seek a balance between ecological protection and social development. China’s MERLs was designated in 2017, but there are problems such as insufficient consideration of areas of high ecological importance and lack of convergence with marine functional zoning. This paper carries out the adjustment of the MERLs in China by constructing the methods of marine ecological importance assessment and human activities disposal assessment, and the results show that after the adjustment, the type and distribution pattern of China’s MERLs is more reasonable, the areas of high ecological importance in the MERLs increases significantly, the intensity of human activities in the MERLs declines significantly, and the unification with the use of marine space is realized. China’s adjustment of the MERLs is based on scientific assessment and realizes the coordination of development and protection, which can provide a reference for global marine ecological protection.

Site-level carbon density data remain limited for many seagrass meadows, especially where the mapped meadow extent has not been paired with repeated carbon-pool measurements. This study quantified biomass carbon density, 0–1 m sediment organic carbon density, total carbon density, and sediment contribution at 10 fixed stations in a meadow dominated by Zostera marina Linnaeus in Caofeidian, Bohai Bay, China, in 2021, 2024, and 2025. Sediment grain-size composition and five water-quality variables were also summarized for 2025 as environmental context. Sediment organic carbon dominated the station-level carbon pool. In 2025, biomass carbon density was 0.269–0.900 Mg C ha−1, sediment organic carbon density was 8.108–39.730 Mg C ha−1, and total carbon density was 8.377–40.566 Mg C ha−1. The median total carbon density was 23.391 Mg C ha−1 in 2021, 18.827 Mg C ha−1 in 2024, and 20.040 Mg C ha−1 in 2025. The rank association between fine sediment fraction and carbon density was positive in 2025 (Spearman’s ρ = 0.491, p = 0.150). These fixed-station records support seagrass monitoring, restoration planning, and sustainable coastal management. They also help link the mapped meadow extent with field carbon data for blue carbon assessment under climate and marine sustainability goals.

Bohai Bay, a semi-enclosed bay in northern China, is an important spawning and nursery ground for marine organisms but has experienced long-term anthropogenic pressures associated with land-based pollution, coastal engineering, and aquaculture activities. Assessing the ecological status of benthic habitats is therefore essential for evaluating the effectiveness of recent management and restoration measures. Based on summer surveys conducted from 2019 to 2023, benthic macrofauna and environmental data were used to evaluate benthic ecological quality in Bohai Bay using three commonly applied indices: the Shannon-Wiener index ( H’ ), AZTI’s Marine Biotic Index (AMBI), and multivariate AMBI (M-AMBI). The three indices showed generally consistent spatial patterns and interannual trends, although differences in sensitivity were observed. H’ and M-AMBI exhibited clearer spatial gradients and higher concordance with habitat conditions, whereas AMBI produced more clustered classifications. Overall, benthic ecological quality in Bohai Bay displayed a significant improving trend during the study period. The proportion of stations classified as slightly disturbed or undisturbed increased from 81% in 2019 to 96% in 2023, while stations in good or high ecological status increased from 56% to 76%. Spatial heterogeneity remained evident, with stations showing moderate disturbance or poor status mainly associated with localized human activities such as aquaculture, anchorage, and marine engineering. Correlation analysis and redundancy analysis further indicated that benthic communities were jointly influenced by water-column and sediment conditions. Active phosphate in the water column was closely associated with broader regional gradients, whereas sediment sulfide played a key role in shaping local benthic ecological quality and community composition. These results indicate that pollution reduction and coastal management efforts have contributed to measurable improvements in benthic ecological quality in Bohai Bay, while localized human pressures continue to influence benthic habitats, and this study provides a multi-index and multivariate framework for assessing benthic ecosystem responses to human activities that supports adaptive management of Bohai Bay and other semi-enclosed coastal systems.

Recognizing Other Effective Area-based Conservation Measures (OECMs) is a critical pathway for achieving the global “30 × 30” biodiversity target. China pioneered the Marine Ecological Redline (MERL) system to safeguard key marine ecosystems, rare and endangered species, and critical habitats through large-scale, legally mandated spatial regulation. However, MERLs have not yet been systematically assessed against OECM criteria. This study evaluates the institutional attributes and ecological effectiveness of MERLs, using the Pearl River Estuary as a case study, and identifies potential OECMs across non-MERL areas in China. The results show that MERLs fully meet OECM criteria, with the Pearl River Estuary MERLs demonstrating marked improvements in water quality, biodiversity recovery, and control of marine development intensity. We provide the first empirical evidence that MERLs function as a nationally led institutional OECM model, which enriches the typology of OECMs and introduces a novel governance pathway for marine biodiversity protection. Furthermore, eight types of non-MERL spatial units were identified as potential marine OECMs. By implementing policy and economic incentive mechanisms and establishing tiered recognition and dynamic identification systems, China can further biodiversity conservation and contribute to the global 30% marine protection goal.

This work presents the design of a β-Ga2O3 MOSFET incorporating a P-type Ga2O3 buffer layer on a high-thermal-conductivity AlN/SiC composite substrate. The electrical characteristics of the device were simulated using Sentaurus TCAD. Results demonstrate that the integration of the composite substrate effectively mitigates self-heating effects, reducing the peak temperature (Tmax) from 776.5 K to 570.9 K at 300 K, while simultaneously increasing the threshold voltage (Vth) from −0.35 V to 1.52 V. Through systematic optimization of the P-Ga2O3 buffer layer thickness and doping concentration, the device achieves a breakdown voltage (Vbr) of 4781 V, a power figure of merit (PFOM) of 2.18 GW/cm2, an IDS, on/off ratio of 9.20 × 109, and cut-off/maximum oscillation frequencies (ft/fmax) of 1.29 GHz and 1.40 GHz, respectively. These findings provide a theoretical foundation for developing β-Ga2O3-based power devices with high breakdown voltage, improved thermal conductivity, and low specific on-resistance (Ron,sp).

Marine benthic habitat mapping is increasingly recognized as an essential tool in integrating available data to inform marine ecosystem-based management. This study presents the first comprehensive and detailed marine benthic habitat map of Bohai Bay, China, utilizing a classification scheme that incorporates both abiotic and biotic features. A total of 20 distinct marine benthic habitat types were identified, reflecting the spatial distribution of reef biota, semi-terrestrial plants, ecologically and economically important benthic communities, as well as areas impacted by anthropogenic activities. This study underscores the value of habitat mapping in providing a robust scientific basis for decision-making and the sustainable utilization of coastal and marine resources in Bohai Bay.

Careful definition and illustrative case studies are fundamental work in developing a Blue Economy. As blue research expands with the world increasingly understanding its importance, policy makers and research institutions worldwide concerned with ocean and coastal regions are demanding further and improved analysis of the Blue Economy. Particularly, in terms of the management connotation, data access, monitoring, and product development, countries are making decisions according to their own needs. As a consequence of this lack of consensus, further dialogue including this cases analysis of the blue economy is even more necessary. This paper consists of four chapters: (I) Understanding the concept of Blue Economy, (II) Defining Blue economy theoretical cases, (III) Introducing Blue economy application cases and (Ⅳ) Providing an outlook for the future. Chapter (II) and Chapter (III) summarizes all the case studies into nine aspects, each aiming to represent different aspects of the blue economy. This paper is a result of knowledge and experience collected from across the global ocean observing community, and is only made possible with encouragement, support and help of all members. Despite the blue economy being a relatively new concept, we have demonstrated our promising exploration in a number of areas. We put forward proposals for the development of the blue economy, including shouldering global responsibilities to protect marine ecological environment, strengthening international communication and sharing development achievements, and promoting the establishment of global blue partnerships. However, there is clearly much room for further development in terms of the scope and depth of our collective understanding and analysis.

Marine spatial planning (MSP) has emerged as a fundamental process for achieving the balanced development of marine ecology, economy, and society. However, increasing conflicts among multiple marine uses, particularly between port development, industrial activities, fisheries, recreation, and ecological protection, highlight the pressing demand for robust and science-based planning tools. In this study, we propose an integrated analytical framework for multi-objective spatial suitability evaluation to optimize MSP. Using the coastal waters of Dalian, China, as a case study, we evaluated the spatial suitability of five key marine activities (ecological protection, mariculture, port construction, wind energy farm development, and coastal tourism) and applied a multi-criteria decision-making approach to inform spatial zoning. The results emphasize the region’s ecological significance as providing critical habitats and migratory corridors for protected and threatened species as well as fishery resources, while also revealing substantial spatial overlaps between conservation priorities and human activities, particularly in nearshore zones. The optimized zoning scheme classifies 22.0% of the coastal waters as Ecological Redline Zones, 32.4% as Ecological Control Zones, and 45.6% as Marine Exploitation Zones. This science-based spatial classification effectively reconciles ecological priorities with development needs, providing a spatially explicit and policy-relevant decision support tool for MSP.

Bohai Bay, a semi-enclosed and ecologically vital bay in northern China, is increasingly threatened by multiple anthropogenic stressors and nutrient enrichment and pollution, particularly excessive nutrient enrichment (cultural eutrophication) from land-based sources (e.g., aquaculture wastewater, riverine input). This study presents a spatially explicit, pressure–sensitivity-based framework to quantify the cumulative impacts of physical loss, physical damage, and eutrophication on subtidal benthic habitats. By integrating spatial data on human uses, eutrophication indices (E), and habitat-specific sensitivity scores, we identified significant spatial heterogeneity in ecological risks, with benthic communities in high-impact zones showing distinct shifts toward pollution-tolerant taxa and degraded ecological quality (e.g., 75% dominance of pollution-tolerant polychaetes). The infralittoral mud habitat, covering ~60% of the bay, was most affected by environmental pressure (31.96% of its area), primarily driven by eutrophication (E>9 in nearshore areas), followed by physical damage (4.72%) and physical loss (0.17%). Although physical loss had a limited spatial extent, its irreversible nature poses high ecological risks. The circalittoral zone, in contrast, faced minimal physical disturbance but remained vulnerable to eutrophication. Our findings highlight the need for differentiated, spatially explicit marine management strategies, particularly for muddy infralittoral habitats where long-term pollution control (e.g., C DIN < 0.5 mg/L) and habitat restoration should be prioritized. This study provides a scientific foundation for conservation planning and ecological risk mitigation in Bohai Bay and similar nutrient-enriched coastal ecosystems globally.